For Arizona Diamondbacks left-hander Patrick Corbin, the story of the 2013 season has taken on two very different chapters.

The first contains a 12-1 start, an All-Star Game appearance and conversations of Cy Young Award contention alongside the likes of Clayton Kershaw and Matt Harvey.

The second and more recent one reads of a 1-4 record with 25 runs and 49 hits allowed in his last seven starts.

So what’s to blame for the 23-year-old’s recent plot change? If you ask Corbin, it’s apparently not the fatigue of playing in his first full season in the majors.

“I feel fine,” Corbin said after Sunday’s 8-2 loss to the San Francisco Giants. “I know it’s baseball. It’s tough. It can be as good as it can get and as bad just as fast. The last two games, I just haven’t been as sharp. I just need to worry about locating and I’ll try to work on that in my bullpen.”

While recent history might suggest otherwise — allowed five or more earned runs in consecutive games for the first time this season — Corbin also has been a hard-luck loser twice (threw quality outings on July 28 against Padres and Aug. 3 against Red Sox) during the seven-start stretch.

When asked if he had discussed the possibility of scaling back his workload over the final month of the season with manager Kirk Gibson, the D-backs’ de facto ace said he didn’t believe such a plan was in his near future.

“My arm feels great, this is just later in the season that this is happen,” said Corbin. “I feel fine and want to keep going out there and pitch. Hopefully get some better innings under my belt.”

Corbin, who holds the sixth-best ERA (2.96) in the National League, is scheduled to make his next start Friday in San Francisco. Including Sunday’s outing, the left-hander is 0-1 with a 3.66 ERA in three starts this season against the Giants.